This invention relates to a combination of a crankshaft and a flywheel. Such combinations are used for internal combustion engines of motor-vehicles. The crankshaft and the flywheel are manufactured separately and must be fastened to each other during the assembly of the combustion engine with a clutch and a gear box. It is highly desirable to provide a crankshaft unit and a flywheel unit which can be easily fastened to each other. This is particularly true in cases in which the flywheel is preassembled with a clutch unit, i.e. a unit comprising a clutch housing fastened to the flywheel, a clutch disc to be connected with a gear box input shaft, a pressure plate connected to the clutch housing for common rotation and axial movement with respect to each other and intended to press the clutch disc against the flywheel, a spring unit acting onto a pressure plate and possibly clutch release means acting onto the pressure plate or the spring unit.